Ink-jet recording apparatus in which a recording head is mounted on a carriage employ a tube supply method in which ink is supplied from an ink tank storing ink to the recording head via a flexible ink supply tube (ink tube).
In tube-supply-type ink-jet recording apparatus, recording is performed as the carriage mounted with the recording head is reciprocated along a guide rod. Therefore, the force of inertia acts on the ink in the ink tube as the carriage is accelerated or decelerated, as a result of which a pressure variation occurs in ink supplied to the recording head. This results in a problem that the pressure variation adversely affects the ink ejection performance of the recording head, which causes a variation in the ink ejection amount, variations in the manner of formation of ink droplets, and other undesirable phenomena, which in turn adversely affects the recording image quality.
One measure which is employed to solve the above problem is to absorb a pressure variation by changing the volume of a buffer room provided in part of an ink channel on the carriage by, for example, forming one side of the buffer room with a flexible film or storing air in the buffer room. JP-A-2004-268448 proposes a technique in which a communication hole is formed at the center of a movable valve. In an ordinary state, the communication hole is located at the same position as the ink channel to enable supply of ink to the recording head. While the carriage is accelerated or decelerated, the communication hole is deviated from the ink channel due to the inertia of the movable valve and the ink supply is thereby restricted.